I was reading over a [url=http://paizo.com/paizo/messageboards/paizoPublishing/pathfinder/pathfinderRPG/communityContent/houseRules/convinceMeThatSpellSaveDCsByLevelMakeSense&page=1#6]post[/url in "Convince me that Save DCs by Spell Level make sense" that got me thinking.
What if the feat, Heighten Spell, also increased the dice limit to the general limit of the level the spell was raised to?
In the 3.0 DMG (pg 95), there was a new spell dice cap chart and Heighten would basically follow that.
Basically, a Heightened Fireball would be nearly identical to a Delayed Blast Fireball.
Dice Limit per level:
0: 1/2 (Acid Splash)
1st: 5 (Burning Hands)
2nd: 10 (Scorching Ray)
3rd: 10 (Fireball)
4th: 15 (Shout)
5th: 15 (Cone of Cold)
6th: 20 (Chain Lightning)
7th: 20 (Delayed Blast Fireball)
8th: 25 (Polar Ray)
9th: 25
Although, this does take some of the wind out of using Empower since you can get 50% more damage from a fireball by making it a level 4 spell instead of a 3rd level spell. But you must be 15th caster level to get those 5 more dice.
Alternatively, you could always bug your DM to make "Fireball 1.1" which is a Fireball at 4th level with a dice cap of 15 dice and "Fireball 1.2" which is at 6th with 20 dice cap.
If a spell does not max out at the charted maximum for the level, the heightened spell maxes out at a proportional value.
IMarv
